Using badges, Project page loads extremely slowly, with ~12s latency (other projects are fine)

Summary

The main page of a project on our GitLab CE installation loads extremely slowly. It is stuck at the beginning for around 12 seconds (btw. the latency time of 12s is quite constant in all attempts so far) and then starts to load the components. Afterwards everything is fast and responds quickly, unless the main project page is clicked again. All other projects load quickly, without interruptions.

Steps to reproduce

Currently I cannot reproduce it with a MWE, so the only way is to go the corresponding project: https://git.km3net.de/km3py/km3pipe

Example Project

https://git.km3net.de/km3py/km3pipe

What is the current bug behavior?

Main page loading hangs for several seconds.

What is the expected correct behavior?

Immediate loading of the main page.

Relevant logs and/or screenshots

Here is the slowly loading project (notice the 12s latency):

Here is another project within the same GitLab group, loading quickly:

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.4.5p335
Gem Version:	2.7.6
Bundler Version:1.16.6
Rake Version:	12.3.1
Redis Version:	3.2.12
Git Version:	2.18.1
Sidekiq Version:5.2.1
Go Version:	unknown

GitLab information
Version:	11.5.0-ee
Revision:	cb71fca
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
DB Version:	9.6.8
URL:		https://git.km3net.de
HTTP Clone URL:	https://git.km3net.de/some-group/some-project.git
SSH Clone URL:	git@git.km3net.de:some-group/some-project.git
Elasticsearch:	no
Geo:		no
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers: google_oauth2

GitLab Shell
Version:	8.4.1
Repository storage paths:
- default: 	/var/opt/gitlab/git-data/repositories
Hooks:		/opt/gitlab/embedded/service/gitlab-shell/hooks
Git:		/opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab Shell ...

GitLab Shell version >= 8.4.1 ? ... OK (8.4.1)
hooks directories in repos are links: ...
4/1 ... ok
5/2 ... ok
6/3 ... ok
5/4 ... ok
5/5 ... ok
5/6 ... ok
5/7 ... ok
5/8 ... ok
5/9 ... ok
5/10 ... ok
5/11 ... ok
5/12 ... ok
5/13 ... ok
6/14 ... ok
7/15 ... repository is empty
6/16 ... ok
6/17 ... ok
6/18 ... ok
6/19 ... ok
6/20 ... ok
77/21 ... ok
3/22 ... ok
3/23 ... ok
4/24 ... ok
3/25 ... ok
3/26 ... ok
3/27 ... ok
3/28 ... ok
3/29 ... ok
2/30 ... ok
3/31 ... ok
2/32 ... ok
2/33 ... ok
2/34 ... ok
15/36 ... ok
15/37 ... ok
15/38 ... ok
15/39 ... ok
2/41 ... ok
17/46 ... ok
17/47 ... ok
17/48 ... ok
15/49 ... ok
19/50 ... ok
19/51 ... ok
20/52 ... ok
20/54 ... ok
20/55 ... ok
20/56 ... ok
21/58 ... repository is empty
15/59 ... ok
29/60 ... ok
34/61 ... ok
36/62 ... ok
22/63 ... ok
22/64 ... ok
32/66 ... ok
32/67 ... ok
41/68 ... ok
22/69 ... repository is empty
22/70 ... ok
2/73 ... ok
11/75 ... ok
22/76 ... ok
36/77 ... repository is empty
46/79 ... ok
46/80 ... ok
46/81 ... ok
46/82 ... ok
46/83 ... ok
46/84 ... ok
46/85 ... ok
41/86 ... ok
18/87 ... ok
18/88 ... ok
2/89 ... ok
43/90 ... ok
32/91 ... ok
6/92 ... ok
22/93 ... ok
6/95 ... ok
53/96 ... ok
6/98 ... ok
6/99 ... ok
53/100 ... ok
60/103 ... ok
22/104 ... ok
51/105 ... ok
6/106 ... ok
22/107 ... ok
3/108 ... ok
77/109 ... ok
56/114 ... ok
41/115 ... ok
65/116 ... ok
65/117 ... ok
65/118 ... ok
65/119 ... ok
65/120 ... ok
6/122 ... ok
35/123 ... ok
40/124 ... ok
6/125 ... ok
34/126 ... ok
6/127 ... ok
45/128 ... ok
67/129 ... ok
43/130 ... ok
22/131 ... ok
4/132 ... ok
69/133 ... ok
69/135 ... ok
46/136 ... ok
2/137 ... repository is empty
29/138 ... ok
69/139 ... ok
28/140 ... ok
14/141 ... ok
6/142 ... ok
2/143 ... ok
10/144 ... ok
10/145 ... ok
34/146 ... ok
60/148 ... ok
6/149 ... ok
76/152 ... ok
3/154 ... ok
2/155 ... ok
73/157 ... ok
4/158 ... ok
2/159 ... ok
32/160 ... ok
74/161 ... ok
32/162 ... ok
81/163 ... ok
48/164 ... ok
75/165 ... ok
75/166 ... ok
76/167 ... ok
80/168 ... ok
2/169 ... ok
2/176 ... ok
2/177 ... ok
32/178 ... ok
89/180 ... repository is empty
40/181 ... ok
75/182 ... ok
50/183 ... ok
75/184 ... ok
75/185 ... ok
75/186 ... ok
91/188 ... ok
92/189 ... ok
75/191 ... ok
22/192 ... ok
52/193 ... ok
34/194 ... ok
50/195 ... ok
2/196 ... ok
3/197 ... ok
2/198 ... ok
87/199 ... ok
46/200 ... ok
34/201 ... ok
88/203 ... ok
46/204 ... ok
2/205 ... ok
55/206 ... ok
46/207 ... ok
2/208 ... ok
51/209 ... ok
32/210 ... ok
34/211 ... ok
32/212 ... ok
22/214 ... ok
2/216 ... ok
98/217 ... ok
29/220 ... ok
65/221 ... ok
75/223 ... ok
75/224 ... ok
76/225 ... ok
76/227 ... ok
2/228 ... ok
76/234 ... ok
103/236 ... ok
75/237 ... ok
76/238 ... ok
76/239 ... ok
103/240 ... ok
2/241 ... ok
76/242 ... ok
103/243 ... ok
73/244 ... ok
103/246 ... ok
108/247 ... ok
104/248 ... ok
104/249 ... ok
104/250 ... ok
22/251 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK

Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful

Checking GitLab Shell ... Finished

Checking Gitaly ...

default ... OK

Checking Gitaly ... Finished

Checking Sidekiq ...

Running? ... yes
Number of Sidekiq processes ... 1

Checking Sidekiq ... Finished

Reply by email is disabled in config/gitlab.yml
Checking LDAP ...

LDAP is disabled in config/gitlab.yml

Checking LDAP ... Finished

Checking GitLab ...

Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
4/1 ... yes
5/2 ... yes
6/3 ... yes
5/4 ... yes
5/5 ... yes
5/6 ... yes
5/7 ... yes
5/8 ... yes
5/9 ... yes
5/10 ... yes
5/11 ... yes
5/12 ... yes
5/13 ... yes
6/14 ... yes
7/15 ... yes
6/16 ... yes
6/17 ... yes
6/18 ... yes
6/19 ... yes
6/20 ... yes
77/21 ... yes
3/22 ... yes
3/23 ... yes
4/24 ... yes
3/25 ... yes
3/26 ... yes
3/27 ... yes
3/28 ... yes
3/29 ... yes
2/30 ... yes
3/31 ... yes
2/32 ... yes
2/33 ... yes
2/34 ... yes
15/36 ... yes
15/37 ... yes
15/38 ... yes
15/39 ... yes
2/41 ... yes
17/46 ... yes
17/47 ... yes
17/48 ... yes
15/49 ... yes
19/50 ... yes
19/51 ... yes
20/52 ... yes
20/54 ... yes
20/55 ... yes
20/56 ... yes
21/58 ... yes
15/59 ... yes
29/60 ... yes
34/61 ... yes
36/62 ... yes
22/63 ... yes
22/64 ... yes
32/66 ... yes
32/67 ... yes
41/68 ... yes
22/69 ... yes
22/70 ... yes
2/73 ... yes
11/75 ... yes
22/76 ... yes
36/77 ... yes
46/79 ... yes
46/80 ... yes
46/81 ... yes
46/82 ... yes
46/83 ... yes
46/84 ... yes
46/85 ... yes
41/86 ... yes
18/87 ... yes
18/88 ... yes
2/89 ... yes
43/90 ... yes
32/91 ... yes
6/92 ... yes
22/93 ... yes
6/95 ... yes
53/96 ... yes
6/98 ... yes
6/99 ... yes
53/100 ... yes
60/103 ... yes
22/104 ... yes
51/105 ... yes
6/106 ... yes
22/107 ... yes
3/108 ... yes
77/109 ... yes
56/114 ... yes
41/115 ... yes
65/116 ... yes
65/117 ... yes
65/118 ... yes
65/119 ... yes
65/120 ... yes
6/122 ... yes
35/123 ... yes
40/124 ... yes
6/125 ... yes
34/126 ... yes
6/127 ... yes
45/128 ... yes
67/129 ... yes
43/130 ... yes
22/131 ... yes
4/132 ... yes
69/133 ... yes
69/135 ... yes
46/136 ... yes
2/137 ... yes
29/138 ... yes
69/139 ... yes
28/140 ... yes
14/141 ... yes
6/142 ... yes
2/143 ... yes
10/144 ... yes
10/145 ... yes
34/146 ... yes
60/148 ... yes
6/149 ... yes
76/152 ... yes
3/154 ... yes
2/155 ... yes
73/157 ... yes
4/158 ... yes
2/159 ... yes
32/160 ... yes
74/161 ... yes
32/162 ... yes
81/163 ... yes
48/164 ... yes
75/165 ... yes
75/166 ... yes
76/167 ... yes
80/168 ... yes
2/169 ... yes
2/176 ... yes
2/177 ... yes
32/178 ... yes
89/180 ... yes
40/181 ... yes
75/182 ... yes
50/183 ... yes
75/184 ... yes
75/185 ... yes
75/186 ... yes
91/188 ... yes
92/189 ... yes
75/191 ... yes
22/192 ... yes
52/193 ... yes
34/194 ... yes
50/195 ... yes
2/196 ... yes
3/197 ... yes
2/198 ... yes
87/199 ... yes
46/200 ... yes
34/201 ... yes
88/203 ... yes
46/204 ... yes
2/205 ... yes
55/206 ... yes
46/207 ... yes
2/208 ... yes
51/209 ... yes
32/210 ... yes
34/211 ... yes
32/212 ... yes
22/214 ... yes
2/216 ... yes
98/217 ... yes
29/220 ... yes
65/221 ... yes
75/223 ... yes
75/224 ... yes
76/225 ... yes
76/227 ... yes
2/228 ... yes
76/234 ... yes
103/236 ... yes
75/237 ... yes
76/238 ... yes
76/239 ... yes
103/240 ... yes
2/241 ... yes
76/242 ... yes
103/243 ... yes
73/244 ... yes
103/246 ... yes
108/247 ... yes
104/248 ... yes
104/249 ... yes
104/250 ... yes
22/251 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.4.5)
Git version >= 2.9.5 ? ... yes (2.18.1)
Git user has default SSH configuration? ... yes
Active users: ... 90
Elasticsearch version 5.1 - 5.5? ... skipped (elasticsearch is disabled)

Checking GitLab ... Finished

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)